High mobility group box 1 promotes sorafenib resistance in HepG2 cells and in vivo

Targeting cell death mechanisms: the potential of autophagy and ferroptosis in hepatocellular carcinoma therapy

Ferroptosis is a type of cell death that plays a remarkable role in the growth and advancement of malignancies including hepatocellular carcinoma (HCC). Non-coding RNAs (ncRNAs) have a considerable impact on HCC by functioning as either oncogenes or suppressors. Recent research has demonstrated that non-coding RNAs (ncRNAs) have the ability to control ferroptosis in HCC cells, hence impacting the advancement of tumors and the resistance of these cells to drugs. Autophagy is a mechanism that is conserved throughout evolution and plays a role in maintaining balance in the body under normal settings. Nevertheless, the occurrence of dysregulation of autophagy is evident in the progression of various human disorders, specifically cancer. Autophagy plays dual roles in cancer, potentially influencing both cell survival and cell death. HCC is a prevalent kind of liver cancer, and genetic mutations and changes in molecular pathways might worsen its advancement. The role of autophagy in HCC is a subject of debate, as it has the capacity to both repress and promote tumor growth. Autophagy activation can impact apoptosis, control proliferation and glucose metabolism, and facilitate tumor spread through EMT. Inhibiting autophagy can hinder the growth and spread of HCC and enhance the ability of tumor cells to respond to treatment. Autophagy in HCC is regulated by several signaling pathways, such as STAT3, Wnt, miRNAs, lncRNAs, and circRNAs. Utilizing anticancer drugs to target autophagy may have advantageous implications for the efficacy of cancer treatment.

Calunduloside E inhibits HepG2 cell proliferation and migration via p38/JNK-HMGB1 signalling axis

High-mobility group box 1 (HMGB1), a highly conserved chromosome protein, is considered as a potential therapeutic target and novel biomarker because of its regulation in the proliferation and metastasis of Hepatocellular carcinoma (HCC). Calenduloside E (CE), a natural active product, has been reported to anti-cancer effect. However, the role and underlying molecular mechanism of CE in HCC is still unclear. The purpose of this study is to investigate the effects of CE on the proliferation and migration of HCC, and then explore the possible underlying molecular mechanism. HepG2 cells were treated with CE or transfected with HMGB1 shRNA plasmids, EdU and colony formation assays were used to detect cell proliferation ability. Wound healing and transwell assays were used to determine the role of CE in cell migration. The expression of Cyclins, PCNA, MMPs, HMGB1, N-cadherin, E-cadherin and phosphorylation of p38, ERK and JNK were all detected using Western blotting. Our results showed that CE inhibited HepG2 cells proliferation and migration in a dose dependent manner; reduced the expression levels of Cycins, PCNA, HMGB1, MMPs and N-cadherin; up-regulated E-cadherin expression; enhanced the phosphorylation of p38 and JNK signalling pathways. Blocking the activation of p38 and JNK obviously reversed CE-mediated inhibitory effects on HepG2 cell proliferation and migration; reversed CE-induced down-regulation of Cyclins, PCNA, MMPs, N-cadherin and HMGB1, as well as E-cadherin up-regulation. In conclusion, our study suggested that CE reduces the expression levels of Cyclins, MMPs and epithelial-mesenchymal transformation (EMT) through p38/JNK-HMGB1 signaling axis and then inhibits HepG2 cells proliferation and migration in HepG2 cells. This study provides a new perspective for the anti-tumour molecular mechanism of CE in HCC.

Establishment of a pattern recognition metabolomics model for the diagnosis of hepatocellular carcinoma

BACKGROUND

Early diagnosis of hepatocellular carcinoma may help to ensure that patients have a chance for long-term survival; however, currently available biomarkers lack sensitivity and specificity.

AIM

To characterize the serum metabolome of hepatocellular carcinoma in order to develop a new metabolomics diagnostic model and identifying novel biomarkers for screening hepatocellular carcinoma based on the pattern recognition method.

METHODS

Ultra-performance liquid chromatography-mass spectroscopy was used to characterize the serum metabolome of hepatocellular carcinoma (n = 30) and cirrhosis (n = 29) patients, followed by sequential feature selection combined with linear discriminant analysis to process the multivariate data.

RESULTS

The concentrations of most metabolites, including proline, were lower in patients with hepatocellular carcinoma, whereas the hydroxypurine levels were higher in these patients. As ordinary analysis models failed to discriminate hepatocellular carcinoma from cirrhosis, pattern recognition analysis was used to establish a pattern recognition model that included hydroxypurine and proline. The leave-one-out cross-validation accuracy and area under the receiver operating characteristic curve analysis were 95.00% and 0.90 [95% Confidence Interval (CI): 0.81-0.99] for the training set, respectively, and 78.95% and 0.84 (95%CI: 0.67-1.00) for the validation set, respectively. In contrast, for α-fetoprotein, the accuracy and area under the receiver operating characteristic curve were 65.00% and 0.69 (95%CI: 0.52-0.86) for the training set, respectively, and 68.42% and 0.68 (95%CI: 0.41-0.94) for the validation set, respectively. The Z test revealed that the area under the curve of the linear discriminant analysis model was significantly higher than the area under the curve of α-fetoprotein (P < 0.05) in both the training and validation sets.

CONCLUSION

Hydroxypurine and proline might be novel biomarkers for hepatocellular carcinoma, and this disease could be diagnosed by the metabolomics model based on pattern recognition.

High Mobility Group Box 1 in Human Cancer

High mobility group box 1 (HMGB1) is an extremely versatile protein that is located predominantly in the nucleus of quiescent eukaryotic cells, where it is critically involved in maintaining genomic structure and function. During cellular stress, however, this multifaceted, cytokine-like protein undergoes posttranslational modifications that promote its translocation to the cytosol, from where it is released extracellularly, either actively or passively, according to cell type and stressor. In the extracellular milieu, HMGB1 triggers innate inflammatory responses that may be beneficial or harmful, depending on the magnitude and duration of release of this pro-inflammatory protein at sites of tissue injury. Heightened awareness of the potentially harmful activities of HMGB1, together with a considerable body of innovative, recent research, have revealed that excessive production of HMGB1, resulting from misdirected, chronic inflammatory responses, appears to contribute to all the stages of tumorigenesis. In the setting of established cancers, the production of HMGB1 by tumor cells per se may also exacerbate inflammation-related immunosuppression. These pro-inflammatory mechanisms of HMGB1-orchestrated tumorigenesis, as well as the prognostic potential of detection of elevated expression of this protein in the tumor microenvironment, represent the major thrusts of this review.

microRNA-548b suppresses aggressive phenotypes of hepatocellular carcinoma by directly targeting high-mobility group box 1 mRNA

Background and purpose: An increasing number of studies have revealed that microRNAs (miRNAs) are the main drivers of hepatocarcinogenesis including progression to later stages of liver cancer. Recently, miR-548b was identified as a cancer-related miRNA in glioma and tongue squamous cell carcinoma. Nonetheless, the expression pattern and specific roles of miR-548b in hepatocellular carcinoma (HCC) have not yet been clarified.

Methods: Expression levels of miR-548b in HCC tissues and cell lines were measured by reverse-transcription quantitative PCR. In vitro and in vivo functional assays were performed to determine the effects of miR-548b on the malignant phenotypes of HCC cells. In addition, the molecular mechanisms by which miR-548b regulates the initiation and progression of HCC were investigated in detail.

Results: miR-548b expression was weak in HCC tissues and cell lines. The low miR-548b expression significantly correlated with tumor size, TNM stage, and venous infiltration of HCC. In addition, exogenous miR-548b expression suppressed HCC cell proliferation, colony formation, and metastasis and induced apoptosis in vitro. Silencing of miR-548b exerted an opposite effect on these characteristics of HCC cells. Furthermore, miR-548b overexpression hindered tumor growth in vivo. Mechanistic analysis identified high-mobility group box 1 (HMGB1) as a direct target gene of miR-548b in HCC cells. Moreover, an HMGB1 knockdown reproduced the effects of miR-548b upregulation on HCC cells. Recovered HMGB1 expression reversed the effects of miR-548b on HCC cells. Notably, miR-548b overexpression deactivated the PI3K–AKT pathway in HCC cells in vitro and in vivo.

Conclusion: Our findings provide the first evidence that miR-548b restrains HCC progression, at least partially, by downregulating HMGB1 and deactivating the PI3K–AKT pathway. Thus, miR-548b might be a novel target for the development of new therapies for HCC.

Targeting High Mobility Group Box-1 (HMGB1) Promotes Cell Death in Myelodysplastic Syndrome

PURPOSE

Myelodysplastic syndrome (MDS) is associated with a dysregulated innate immune system. The purpose of this study was to determine whether modulation of the innate immune system via high mobility group box-1 (HMGB1) could reduce cell viability in MDS.

EXPERIMENTAL DESIGN

We quantified HMGB1 in an MDS cell line MDS-L and in primary MDS cells compared with nonmalignant hematopoietic cells. We performed loss-of-function studies of HMGB1 using pooled siRNAs and a small-molecule inhibitor sivelestat compared with standard chemotherapy. We measured levels of engraftment of MDS-L cells in NOD-scidIL2Rg^null (NSG) mice following treatment with sivelestat. Mechanistically, we interrogated cell survival pathways and 45 targets within the NFκB pathway using both protein analysis and a proteome profiler array.

RESULTS

We discovered that HMGB1 had increased expression in both MDS-L cells and in primary CD34⁺ MDS cells compared with healthy CD34⁺ hematopoietic cells. Sivelestat impaired MDS cell expansion, increased cellular death, and spared healthy hematopoietic cells. MDS-L marrow engraftment is reduced significantly at 17 weeks following treatment with sivelestat compared with control mice. Treatment of CD34⁺ MDS cells with sivelestat and azacitidine or decitabine was additive to increase apoptotic cell death compared with chemotherapy alone. Sivelestat promoted apoptosis with increased expression of PUMA, activated caspase 3, and increased DNA double-strand breaks. Inhibition of HMGB1 reduced levels of Toll-like receptors (TLR) and suppressed activation of NFκB in MDS-L cells.

CONCLUSIONS

Inhibition of HMGB1 could promote MDS cell death and alter innate immune responses via suppression of NFκB pathways.

Secretory High-Mobility Group Box 1 Protein Affects Regulatory T Cell Differentiation in Neuroblastoma Microenvironment In Vitro

Neuroblastoma (NB) is the most common extracranial tumor of childhood with poor prognosis in a high-risk group. An obstacle in the development of treatment for solid tumors is the immunosuppressive nature of the tumor microenvironment (TME). Regulatory T cells (Tregs) represent a T cell subset with specialized function in immune suppression and maintaining self-tolerance. Tregs resident within the tumor milieu is believed to play an important role in immune escape mechanisms. The role of the NB microenvironment in promoting Treg phenotype has never been elucidated. Herein, we demonstrated that the NB microenvironment promoted T cell activation and one NB cell line, SK-N-SH, manifested an ability to induce Treg differentiation. We identified tumor-derived HMGB1 as a potential protein responsible for Treg phenotype induction. By neutralizing HMGB1, Treg differentiation was abolished. Finally, we adopted a dataset of 498 pediatric NB via the NCBI GEO database, accession GSE49711, to validate clinical relevance of HMGB1 overexpression. Up to 11% of patients had HMGB1-overexpressed tumors. Moreover, this patient subpopulation showed higher risks of tumor progression, relapse, or death. Our findings emphasize the importance of immunological signature of tumor cells for appropriate therapeutic approach. Upregulation of secretory HMGB1 may contribute to suppression of antitumor immunity through induction of Tregs in the NB microenvironment.

Role of autophagy in tumorigenesis, metastasis, targeted therapy and drug resistance of hepatocellular carcinoma

Autophagy is a “self-degradative” process and is involved in the maintenance of cellular homeostasis and the control of cellular components by facilitating the clearance or turnover of long-lived or misfolded proteins, protein aggregates, and damaged organelles. Autophagy plays a dual role in cancer, including in tumor progression and tumor promotion, suggesting that autophagy acts as a double-edged sword in cancer cells. Liver cancer is one of the greatest leading causes of cancer death worldwide due to its high recurrence rate and poor prognosis. Especially in China, liver cancer has become one of the most common cancers due to the high infection rate of hepatitis virus. In primary liver cancer, hepatocellular carcinoma (HCC) is the most common type. Considering the perniciousness and complexity of HCC, it is essential to elucidate the function of autophagy in HCC. In this review, we summarize the physiological function of autophagy in cancer, analyze the role of autophagy in tumorigenesis and metastasis, discuss the therapeutic strategies targeting autophagy and the mechanisms of drug-resistance in HCC, and provide potential methods to circumvent resistance and combined anticancer strategies for HCC patients.

High-Mobility Group Box-1 and Liver Disease

High‐mobility group box‐1 (HMGB1) is a ubiquitous protein. While initially thought to be simply an architectural protein due to its DNA‐binding ability, evidence from the last decade suggests that HMGB1 is a key protein participating in the pathogenesis of acute liver injury and chronic liver disease. When it is passively released or actively secreted after injury, HMGB1 acts as a damage‐associated molecular pattern that communicates injury and inflammation to neighboring cells by the receptor for advanced glycation end products or toll‐like receptor 4, among others. In the setting of acute liver injury, HMGB1 participates in ischemia/reperfusion, sepsis, and drug‐induced liver injury. In the context of chronic liver disease, it has been implicated in alcoholic liver disease, liver fibrosis, nonalcoholic steatohepatitis, and hepatocellular carcinoma. Recently, specific posttranslational modifications have been identified that could condition the effects of the protein in the liver. Here, we provide a detailed review of how HMGB1 signaling participates in acute liver injury and chronic liver disease.

miR-505 enhances doxorubicin-induced cytotoxicity in hepatocellular carcinoma through repressing the Akt pathway by directly targeting HMGB1

Compelling evidence has suggested the relevance of miRNAs in resistance to chemotherapeutic agents in HCC. miR-505 was reported to be downregulated and function as a tumor suppressor in HCC cells by binding to high-mobility group box 1 (HMGB1). Whether miR-505/HMGB1 axis was involved in ADM cytotoxicity in HCC remains to be addressed. The aim of this study was to explore the effect of miR-505/HMGB1 axis on ADM cytotoxicity in HCC cells. MTT, flow cytometry analysis, and caspase-3 activity assays were conducted to assess ADM-induced cytotoxicity. The protein level of phosphorylation of histone H2 AX at Ser139 (γH2AX) was detected to evaluate DNA damage. The effects of miR-505 and HMGB1 on the protein kinase B (Akt) pathway were determined by examining the protein levels of phosphorylated Akt (p-Akt), Akt, phosphorylated glycogen synthase kinase-3β (p-GSK-3β), and GSK-3β. We found that HMGB1 knockdown and miR-505 overexpression exacerbated ADM-induced cell viability inhibition, enhanced ADM-induced apoptosis, and increased caspase-3 activity in ADM-treated HCC cells. However, HMGB1 overexpression reversed the effects of miR-505 on ADM-induced cytotoxicity in HCC cells. HMGB1 knockdown and miR-505 overexpression promoted ADM-induced DNA damage in HCC cells, which was abated by HMGB1 overexpression. On a molecular mechanism level, HMGB1 silencing and miR-505 overexpression inactivated the Akt pathway in HCC cells, while exogenous HMGB1 resisted miR-505-induced Akt pathway inactivation. In conclusion, miR-505 overexpression enhanced ADM-induced cytotoxicity in HCC cells, at least partly by targeting HMGB1 and inactivating the Akt pathway.